v3.25.0.1
Regulation (Tables)
 12 Months Ended
Dec. 31, 2024
Regulated Operations [Abstract]  
Schedule of Nature of Regulation
Nature of Regulation
Allowed
Common
Equity
(%)
Allowed ROE (1)
(%)

Regulated Utility		Regulatory Authority20242023Significant Features
ITC
Federal Energy Regulatory Commission ("FERC")60.0 

10.73
(2)
10.77
(2)
Cost-based formula rates, with annual true-up mechanism (3)
Incentive adders
TEP
Arizona Corporation Commission ("ACC") 54.3 9.55 9.55 
(4)
COS regulation
Historical test year
FERC
(5)
9.79 9.79 Formula transmission rates
UNS ElectricACC53.7 9.75 
(6)
9.50 
UNS GasACC50.8 
9.75
(7)
9.75 
Central Hudson New York State Public Service Commission ("PSC")
48.0
9.50
(8)
9.00 COS regulation
Future test year
FortisBC Energy British Columbia Utilities Commission ("BCUC")45.0 
9.65
9.65 COS regulation with formula components and incentives
FortisBC ElectricBCUC41.0 
9.65
9.65 Future test year
FortisAlbertaAlberta Utilities Commission ("AUC")37.0 
9.28
8.50 
PBR, with formula to calculate ROE on an annual basis (9)
Newfoundland PowerNewfoundland and Labrador Board of Commissioners of Public Utilities45.0 
8.50
8.50 COS regulation
Future test year
Maritime ElectricIsland Regulatory and Appeals Commission40.0 
9.35
9.35
COS regulation
Future test year
FortisOntario (10)
Ontario Energy Board40.0 
8.52-9.30
8.52-9.30
COS regulation with incentive mechanisms
Caribbean Utilities (11)
Utility Regulation and Competition OfficeN/A
8.25-10.25
7.50-9.50
COS regulation
Rate-cap adjustment mechanism
based on published consumer price indices
FortisTCI (12)
Government of the Turks and Caicos IslandsN/A
15.00-17.50
15.00-17.50
COS regulation
Historical test year

(1)    ROA for Caribbean Utilities and FortisTCI
(2)    Reflects the allowed common equity and ROE for ITCTransmission, METC, and ITC Midwest. The ROE above is inclusive of the base ROE as well as incentive adders totalling 0.75%. FERC issued an order in October 2024 retroactively revising the base ROE to certain prior periods including 2023. See "Significant Regulatory Matters" below
(3)    Annual true-up collected or refunded in rates within a two-year period
(4)    Allowed common equity of 54.3% and ROE of 9.55% effective September 1, 2023
(5)    The allowed common equity component for FERC transmission rates is formulaic, and is updated annually based on TEP's actual equity ratio
(6)    Allowed common equity of 53.7% and ROE of 9.75% effective February 1, 2024
(7)    A general rate application requesting new customer rates is ongoing. See "Significant Regulatory Matters" below
(8)    ROE of 9.5% effective July 1, 2024. A general rate application requesting new customer rates effective July 1, 2025 is ongoing. See "Significant Regulatory Matters" below
(9)    In 2023, FortisAlberta was subject to a COS revenue requirement. The ROE for 2025 has been set at 8.97%
(10)    Two of FortisOntario's utilities follow COS regulation with incentive mechanisms, while the remaining utility is subject to a 35-year franchise agreement expiring in 2033
(11)    Operates under licences from the Government of the Cayman Islands. Its exclusive transmission and distribution licence is for an initial 20-year period, expiring in April 2028, with a provision for automatic renewal. Its non-exclusive generation licence is for a 25-year term, expiring in November 2039
(12)    Operates under 25 and 50 year licences from the Government of the Turks and Caicos Islands, which expire in 2036 and 2037, respectively